What material is A335 P91 steel pipe?

For A335 P91 steel pipe, A335 refers to the executive standard - American Standard ASTM A335 / A335M, and P91 steel pipe produced under this standard is seamless ferrite alloy steel pipe for high temperature.

Chemical composition of A335 P91 steel pipe:
C 0.08 - 0.12, Mn 0.30 - 0.60, Si 0.20 - 0.50, P ≤0.02, S ≤0.01, Cr 8.0 - 9.5, Mo 0.85 - 1.05, V 0.18 - 0.25, Nb 0.06 - 0.1, N 0.03 - 0.07, Al ≤0.04, Ni ≤0.4.

Mechanical properties of A335 P91 steel pipe: tensile strength 585 MPa, yield strength 415 MPa, elongation 20%.